Telephone-exchange system.



H. P. CLAUSEN.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED APR. 24, 1917.

L5fi6L I Patented M019, 1918,

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HENRY P. CLAUSEN, OF MOUNT VERNON, NEW YORK, ASSIGNOR TO WESTERNELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEWYORK.

Specification of Letters Patent.

Patented Feb. 19, 1918.

Application filed April 24, 1917. Serial No. 164,231.

To. all 'whom it may concern Be it known that I, HENRY P. CLAUSEN, acitizen of the United States, residing at Mount Vernon, in the county ofWestchester and State of New York, have invented certain new and usefulImprovements in Telephone-Exchange Systems, of which the following is afull, clear, concise, and exact description.

This invention relates to telephone exchange systems, and is moreparticularly adapted to provide means for taking care of waitingconnections. The particular objects of the invention and its uses willbe apparent from a description of the embodiment of the invention.

The drawing illustrates diagrammatically portions of a telephoneexchange system showing an embodiment of this invention.

Referring to the drawing and to the embodiment of the invention as showntherein. At Y is shown a telephone line which extends from a subscribersstation Z to a central oflice W. The line Y is connected to the centraloflice with a plurality of sets of terminals J, J, J,, J J It ispreferred that these jacks or sets of terminals be grouped,corresponding terminals of each set of each group beinginterconnected.In the embodiment shown two groups are illustrated, J and J 3constituting one group, and the other three jacks a second group. Theline relay and the line lamp of the line are shown at C and D,respectively, preferably more closely associated with one of the jacks,for example jack J,. The other two jacks of this group may be what areknown as multiple acks as here shown at different operators positions.All of the jacks are normally dis- .connected from the line. The jacks Jand J which are at different operators positions, are adapted to beconnected to the line Y by a relay A. A portion of the connecting orlink circuit here shown as a cord circult is shown at V and a portion ofanother cord circuit is shown at U. The cord circuits U and V may be atdifferent operators positions. Electromagnetic relays are shown at A, B,C, F, H and G. The relay F is of relatively low resistance and the relayB is.

sluggish or slow-acting for purposes which will appear in thedescription of the operation. At M is shown a special test tone devicewhich produces in its circuit N a fluctuating current which is inducedthrough the repeating coil 0 into acircuit including the conductor 40. I

The operation of the system is as follows, assuming that the subscriberat Z is connected through the line Y, the jack J and the plug P and cordcircuit U with another subscribers line and conversation is takingplace. Under these conditions relay A is ope-rated over a circuit frombattery through sleeve contacts 42 and 41 of the plug P and the jack J,and the winding of relay A to ground, thereby closing the switches 9 and10 and completing the connection of the subscriber Z to the cord circuitU. The connection through the cord circuit U to the other line will beunderstood, as standard equipment is employed. The sleeve contact A l ofthe jack J 3 will be at a potential for the purpose of giving theordinary or normal busy test should this jack be tested, therebypreventing the connection of another cord circuit with the group ofjacks to which jack J belongs and consequently with line Y. Theoperation of rela A also closes switches 2' and 3, connecting thespecial test tone equipment to the contacts 8, 8 and 8 of the jacks J,,J and J respectively, of the other group, so that should an operatortest one of these jacks she would receive the special test tone from M.The switch 3 closes the circuit of the relay B, which opens the switches5 and 6, disconnecting the line relay C and the line lamp B from line Y.

With the apparatus in this condition and the conversation between thesubscriber at Z and the other subscriber connected to U in progress, itwill be assumed that a sub-' scriber connected to the calling end S ofthe cord circuit V calls for a connection with the subscriber at Z. Theoperator at V tests the jack J, in the usual manner, and, finding thatthe line Y is busy, so informs the subscriber connected to the callingend S of the cord circuit V. Assuming that such subscriber is willing towait until the termination of the conversation in which the subscriber Zis already engaged or for any other reason asks for a waitingconnection, the operator controlling the cord circuit V tests either ofthe jacks J,, J 2 or J; whichever is most convenient, and receiving thespecial tone from the device M, is thereby notified that a waitingconnection may be made with any one of these jacks, assuming that it isthe jack J 1 that is tested, the plug P is inserted into the jack Jcompleting a circuit through the relays G and F, each of which will beoperated, the relay F opening the switch 7 and disconnecting the specialtone apparatus M from the jacks. The relay G will operate, connectingthe machine ringing equipment to the plug P by the use of apparatus in amanner well understood. The normal busy test will also be placed uponthe contacts 8' and 8-through the sleeve 50 of the plug P. When the plugP was inserted into the jack J,, the relay H was connected in multiplewith the winding of relay F, but H will not be 0 erated under theseconditions, since it wi 1 not receive suflicicnt current to operate itas long as it is in multiple with the winding of relay F. While thesubscriber connected at S is waiting, the conversation in which thesubscriber at Z is already engaged is terminated and the operatorwithdraws the plug P from the jack J, interrupting the circuit of therelay A, which releases its armatures, whereupon the switches 2, 3, 9and 10 will be opened, disconnecting the line Y from the jacks J and JThe circuits of the relay B and of the low resistance relay F willthereby be opened, whereupon these relays release their switches. Theopening of switch 2 breaks the shunt of the winding of relay H which isnow energized. The energization of relay H onens the switches 11 and 12before the slow-acting relay B has permitted the closing of the switches5 and 6, thereby preventing the reconnection of the line apparatus C andD to line Y. The energization of relay H also closes switches 13 and 14,connecting the tip and ring springs of the jack J through to the line Y.Ringing current will immediately be applied to the line and thesubscriber at Z recalled. As soon as this subscriber responds, he isplaced in communication with the subscriber connected at S. The relay Halso closes a switch 15, completing a second circuit for the relay Bbefore the relay B had released its switches. Relay H also closes switch16, connecting the. special tone apparatus M through the switch 16 andthe conductor 60 to the sleeve contacts 41 and 44 of jacks J and J Ifnow asecond operator were to test either the contacts 8' or 8", theordinary busy test would be received, but if the sleeve contacts 41 or44 be tested the special test tone would be received, indicatin that awaiting connection might be made with either ofthe jacks J or 7 It willbe seen that this invention provides means capable of institutingwaiting connections without interfering with the conversationprogressing at the time such waiting connection is made. In fact, it ispossible by the use of this invention to establish the waitingconnections without actually connecting the second cord circuit to thewanted line. Just as soon as the first conversation is terminated andthe wanted line freed, the apparatus will immediately and automaticallycomplete the second connection. These results mav be and referably areaccomplished without imposing any additional load or burdens upon therelays in the cord circuits.

What is claimed is:

1. In a telephone system, the combination of a telephone line providedwith two groups of jacks, means to place the normal busy test on onegroup of the line jacks when a cord circuit is connected to one of thejacks test on each jack of the other group when a cord circuit isconnected to a jack of thefirst group.

2'. In a telephone system, the combination of a telephone line providedwith two groups of sets of terminals, a link circuit, means to place onall of the sets of terminals of a group the normal busy test when thelink circuit is connected to a set of terminals thereof, and mechanismto place on each set of terminals of the second group a special tonetest when the link circuit is connected'to a set of terminals of thefirst group.

3. In a telephone system, the combination of two groups of sets ofswitching terminals normally disconnected from the line, a link circuit,devices to connect each group to the from the telephone line, meansacting automatically when the link circuit is connected to a set ofeither group to connect the telephone line to the terminals of theparticular group and prevent the connection of the line to the terminalsof. the other group,

means for placing the normal busy test on a terminal on each set of agroup having the link circuit connected to the one set thereof, andmeans to place upon a terminal of each set of the other group a specialtone test while the link circuit is connected to a set of terminals ofthe other group.

5. In a telephone system, the combination of a telephone line, aplurality of cord circuits, two groups of line jacks, each group havingits terminals connected together and each group being normallydisconnected from the telephone line, means for automatically connectingthe telephone line to a group to which a cord circuit is connected andpreventing the connection of the line to the other group during suchconnection, means for placing the normal busy test upon each jack of thegroup to which the cord circuit is connected, mechanism to place aspecial tone test upon each jack of the second group while the cordcircuit is connected to a jack of the first group, and means todisconnect the special tone mechanism from the jacks of the second groupand place the normal test thereon when another cord circuit is connectedto a jack of the second group.

6. In a telephone system, the combination of two link circuits, twogroups of sets of switching terminals, the corresponding terminals ofeach set in a group being interconnected, a telephone line adapted to beconnected to the sets of terminals of each group, means for placing thenormal busy test upon sets of terminals of a group to which a linkcircuit is connected, mechanism for placing a special tone test upon aterminal of each set of terminals in the second group when a set ofterminals of the first group is thus engaged, and means for removing thespecial tone from the terminals in the second group and placing thenormal busy test thereon when a second link circuit is connected to aset of terminals of the second group.

7. In a telephone system, the combination of two groups of line jacks, acord circuit, a telephone line adapted to be connected to one group onlyat a time, the testing terminal of each jack in the group beingconnected to the testing terminals of the other jacks in the group,means for placing the normal busy test on the testing terminals of thejacks of a group when one of the jacks thereof is connected to the cordcircuit, and mechanism for placing a special test tone on the testingterminals of the jacks of the other group when the cord circuit isconnected to one of the jacks of the first group.

In witness whereof I hereunto subscribe my name this 20th day of AprilA. D., 1917.

HENRY P. CLAUSEN.

